In a mobile communication system, a telecommunications carrier, which provides services, preliminarily sets a transmission parameter of a wireless base station (hereinafter, simply referred to as a “base station”) at the start of a service so as to obtain a desired service area (cell coverage) in a predetermined communication area including a plurality of base stations. A transmission parameter of a base station includes, for example, an antenna tilt angle (an antenna inclination angle) of the base station, transmission power, an azimuth (an angle of the vertical axis of the antenna), and an antenna pattern (antenna directivity), etc. As a method for arithmetic processing of such a transmission parameter, for example, an optimization algorithm is known.
For example, as a publicly-known method to optimize an antenna tilt angle, there is a method to quantify a decrease in inter-cell interference and a decrease in coverage area of a target cell and calculate a ratio of the decrease in coverage area of the target cell to the decrease in interference. In this method, a candidate inclination angle of a base station antenna at which the ratio of the decrease in coverage area of the target cell to the decrease in interference becomes maximum is identified as an optimum tilt angle of the base station antenna.
Furthermore, as a publicly-known method to optimize an antenna configuration, there is an annealing algorithm for adjusting a parameter of the antenna configuration while updating a temperature T so that an average throughput in each predetermined user distribution becomes optimal.
After a transmission parameter of a base station has been set and the operation of a system has been commenced, an initially-planned optimum service area is sometimes not obtained later on by a change of a system operational condition, a change of the wireless environment (for example, a change of a path loss due to a new building), and the like. Therefore, to maintain the quality of a communication service to a user of a mobile communication system, a telecommunications carrier regularly or irregularly executes the above-described optimization algorithm on a computer and adjusts the transmission parameter.    Patent Literature 1: International Publication Pamphlet No. WO 1999/017576    Non Patent Literature 1: Iana Siomina and Di Yuan, Enhancing HSDPA Performance via Automated and Large-scale Optimization of Radio Base Station Antenna Configuration, IEEE, 2008
However, it is difficult to automatically optimize a transmission parameter on an actual field by using the related optimization algorithm. Because, if an optimization algorithm for optimization of a tilt angle of each base station is constantly executed on the actual field, an optimization process is performed even under a situation where there is no need to perform the optimization process, and this causes a problem that the optimization algorithm is not properly executed or is not converged.